- The Lewis lung carcinoma 3LL, a C57BL/6 (H-2b)-originated spontaneous tumor that progresses at the site of transplantation in all mouse strains, produced lung metastases only in mice that shared the H-2D region and the non-H-2 genetic background with the tumor's strain of origin. In vitro cytotoxicity assays revealed that 3LL tumor cells were sensitive to lysis exerted by anti-H-2Db immune effector cells but were relatively resistant to lysis by anti-H-2Kb effector cells. In addition, the 3LL tumor cells could inhibit the anti-H-2Dd response against EL 4 (H-2b) target cells but had almost no inhibitory effect on the anti-H-2Kb response against the same targets. Immunization of C3HeB (H-2k) and B10.D2 (H-2d) mice with 3LL tumor cells resulted in antisera that could preferentially react with H-2Db-positive cells but reacted very weakly with H-2Kb-positive cells. The results indicate that 3LL tumor cells expressed H-2Db cell surface antigens at a high density and seemed to lack membrane glycoproteins that are encoded by the H-2Kb region.